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目的比较不同注射流率下脑CT灌注成像的血流动力学参数,确定1个既能保证数据的准确性,操作上又相对安全的对比剂注射流率。方法24名健康志愿者按对比剂注射流率(4.5、6.0、7.5 m l/s)分为3组,肘前静脉团注对比剂4 s后行CT灌注扫描,利用灌注分析软件进行处理,生成大脑前动脉和上矢状窦的时间-密度曲线(TDC),计算脑灰、白质的血流量(rCBF1、rCBF2)。比较3组间脑血流动力学指标,包括输出静脉起始增强与输入动脉增强达到峰值的时间差(tV0-tAP)、rCBF1、rCBF2,并进行统计学分析。结果3组间的tV0-tAP分别为-3.5 s、-1.5 s、0.2 s,组间差异有统计学意义(F=18.25,P<0.01),两两比较差异均有统计学意义(P<0.05),仅7.5 m l/s组的tAP较tV0提前约0.2 s;3组间的rCBF1、rCBF2差异均有统计学意义(P<0.05);7.5 m l/s组rCBF1、rCBF2分别为(52.8±3.1)m l.m in-1.100 g-1、(21.9±2.4)m l.m in-1.100 g-1。结论使用7.5 m l/s的注射流率能够满足最大斜率模型的前提条件,得到的脑血流量与单光子发射型计算机体层成像(SPECT)非常接近。
Objective To compare the hemodynamic parameters of brain CT perfusion imaging under different injection rates and to determine a single injection rate of contrast medium which can ensure the accuracy of data and the relatively safe operation. Methods Twenty-four healthy volunteers were divided into three groups according to the contrast agent injection rate (4.5,6.0,7.5 ml / s). The antecubital vein was injected with CT contrast agent for 4 seconds and then processed by perfusion analysis software to generate Time-density curves (TDC) of anterior cerebral arteries and superior sagittal sinus were used to calculate cerebral gray and white matter blood flow (rCBF1, rCBF2). The cerebral hemodynamic parameters were compared between the three groups, including the time difference (tV0-tAP), rCBF1, rCBF2 between the initial increase of the output vein and the peak of the input artery enhancement and the statistical analysis. Results The tV0-tAP between the three groups was -3.5 s, -1.5 s, 0.2 s, respectively. The difference between the two groups was statistically significant (F = 18.25, P <0.01), with significant difference between any two groups (P < 0.05). The tAP in 7.5 ml / s group was about 0.2 second earlier than tV0. The differences of rCBF1 and rCBF2 between the three groups were statistically significant (P <0.05). The rCBF1 and rCBF2 in 7.5 ml / 3.1) m lm in-1.100 g-1, (21.9 ± 2.4) m lm in-1.100 g-1. Conclusions Using the injection rate of 7.5 m l / s, the preconditions for the maximum slope model can be satisfied. The resulting cerebral blood flow is very close to that of single photon emission computed tomography (SPECT).